Evaluation of a satellite-derived latent heat flux product in the South China Sea: A comparison with moored buoy data and various products

Latent heat flux in the South China Sea (SCS) mainly based on the Tropical Rain Measuring Mission Microwave Imager (TMI) is compared with the Objectively Analyzed air-sea heat Fluxes (OAFlux), the Goddard Satellite-Based Surface Turbulent Fluxes, version 2 (GSSTF2), the Japanese Ocean Flux Data Sets with use of Remote Sensing Observations (J-OFURO), the European Centre for Medium-Range Weather Forecasts (ECMWF), the National Centers for Environmental Prediction/Department of Energy reanalysis 2 (NCEP2), and International Comprehensive Ocean-Atmosphere Data Set data (ICOADS). These products did not all compare well to in situ data. It is found that TMI latent heat flux and OAFlux approximately reproduce the time variations of buoy data. However, ECMWF and ICOADS were found that had moderate systematic errors with respect to in situ data. All products qualitatively reveal a similar pattern in climatological fields. Although the satellite-derived products are quite similar, TMI latent heat is smaller than those of OAFlux, GSSTF2 and J-OFURO in the northern SCS. The difference between TMI latent heat and ICOADS is large, and the temporal correlation is extremely low in the entire basin except the Luson Strait. This is owned to that the ICOADS hardly reproduces accurate variability in the data-sparse regions. Also the temporal cross-correlation coefficients of between TMI latent heat and ECMWF or NCEP2 are considerably lower in the central SCS, may be affected by the lack of ship observations of ECMWF and NCEP2 there. The present study also compares meridional structures of the zonal averaged latent heat. The TMI latent heat and OAFlux overestimate the other two satellite-derived products during summer, whereas in winter, the TMI latent heat underestimates the other products in the northern regions. Though the examination of the influence of input variables, we note that the underestimation of TMI latent heat flux than other three satellite derived products in the northern region is mainly caused by larger near-surface air humidity there. While, large sea surface saturation humidity contributes to larger ECMWF latent heat flux. On the other hand, lager latent heat flux of NCEP2 in central parts and ICOADS in eastern bands is possibly mainly caused by the difference in winds.